The present invention relates to a mobile power generating unit and particularly relates to a system for mounting a turbine and an electromotive machine, with their rotor axes in substantial alignment with one another, on a trailer for over-the-road transport whereby alignment adjustments at the power generating site are minimized.
Mobile power generating units are well known and typically comprise a turbine and an electromotive machine such as a generator or alternator (herein referred to interchangeably as a generator) mounted either on separate trailers or a single trailer for transport to a power generating site. Typically, the turbine and generator are mounted on different trailers. At the site, the turbine and generator are coupled to one another to form the power generating unit. It will be appreciated that these units are large-scale, heavy and require accurate alignment in use in order to safely and efficiently generate power. This often necessitates deployment of heavy-duty equipment to manipulate one or both of the machines into alignment at the site and, as a result, requires substantial investment in time and labor. Not infrequently, a full week may be required to properly align and adjust the machines for operation. In those power generation units mounting the turbine and generator on a single trailer, the rotors of the turbine and generator are typically connected together by a flexible coupling. While the turbine and generator are in initial alignment prior to transport, it is very difficult to maintain alignment during travel and also to correct for misalignment at start-up, i.e., difficult to realign. This is in part due to the manner of mounting the turbine and generator on the trailering system.
Additionally, with the turbine and generator mounted directly on a single trailer and generating power at the site, torque from the turbine is transmitted directly to the trailer. Because the trailer is not constructed to accommodate torque, the power generating system gradually and unpredictably goes out of alignment.
Accordingly, there has arisen a need for a power generating unit of substantial size and power generating capacity having a capability for over-road transport of the turbine and generator on a single trailer with the drive line initially aligned and enabling angular deflection during transport with minimal alignment adjustments at start-up and reduced capacity for misalignment during operation.
In accordance with a preferred embodiment of the present invention, there is provided a single trailer for transporting an initially aligned turbine and electromotive machine such as a generator or alternator (hereafter referred to as a generator) over-road to a power generation site whereby the system can be readily aligned at the site and maintained in alignment during operation. To accomplish this, the generator is fixed to the trailer. Preferably, the base of the generator is welded to the frame of the trailer, fixing the component parts of the machine, both stationary and rotational components, in exact position. The turbine, however, is fixed to a sub-base. The sub-base, in turn, is pivotally mounted at one end to the generator base, preferably by a pair of transversely spaced clevis mounts. The opposite end of the sub-base is mounted to an isolator fixed to the trailer frame along the centerline of the trailer. This 3-point mounting, i.e., the isolator and the pair of clevis mounts, enable angular deflection of the axis of the turbine relative to the axis of the rotor of the generator during transport. The isolator is, of course, locked down to maintain alignment of the turbine and generator axes during power generation at the site. Preferably, the sub-base is mounted at an end adjacent the generator by the pair of clevis-type pivotal mounts spaced transversely one from the other as widely as possible along opposite sides of the trailer whereby the sub-base is pivotal at its aft end about those pivotal mounts. Because the isolator during transport permits limited vertical angular movement of the end of the turbine opposite the generator, the turbine rotor axis may angularly deflect relative to the generator axis upon over-road pivoting movement of the sub-base and turbine relative to the trailer and the generator. The pivotal mounts are also located at a like longitudinal location along the trailer as a flexible coupling between the turbine and generator rotors. This enables the turbine and generator axes to be maintained in approximate alignment with one another, notwithstanding angular deflection of the sub-base carrying the turbine about the transverse axis of the clevis-type mounts. Additionally, only a very slight lateral deflection of the sub-base mounting the turbine is permitted because of the pinned clevis-type connection between the sub-base and the base of the generator. The springs in the isolator maintain the end of the sub-base opposite the generator base in a central position limiting vertical and lateral deflections.
Not only is the initial alignment maintained during transport, minimizing the requirement for substantial alignment at the power generation site, but the foregoing described 3-point mounting also enables the torque of the turbine to be transferred directly from the turbine sub-base into the generator base rather than directly to the trailer. With this 3-point mounting, torque from the turbine is transferred through the pivot pins directly to the generator base. Preferably, the pivot mounts for the sub-base are located as wide apart as possible, given over-road transport requirements. This is significant because if the torque was transferred directly to the trailer, the turbine and generator axes would gradually and unpredictably move out of alignment. The trailer is not designed to absorb the torque of the turbine and, hence, in accordance with the present invention, the torque is transferred directly from the turbine to the generator base rather than directly to the trailer underlying the turbine.
In a preferred embodiment according to the present invention, there is provided a system for transporting a power generation unit comprising an elongated trailer mounted on a plurality of wheels on axles spaced from one another along the length of the trailer, an electromotive machine having a rotor rotatable about an axis and disposed on the trailer, the machine being secured to the trailer and being located with the rotor axis extending in a length direction of the trailer, a sub-base, a turbine having a rotor rotatable about an axis and fixed to the sub-base, the turbine and the electromotive machine being mounted on the sub-base and the trailer, respectively, with the rotor axes thereof in substantial axial alignment relative to one another, the sub-base adjacent an end thereof proximate the electromotive machine being connected to the trailer for pivotal movement about a transverse axis normal to the length direction of the trailer and a mounting between the trailer and the sub-base adjacent an opposite end of the sub-base remote from the electromotive machine limiting joint pivotal movement of the sub-base and an opposite end of the turbine from the electromotive machine about the transverse axis in a generally vertical direction whereby the axes of the rotors are maintained in approximate axial alignment relative to one another during transport of the power generation unit on the trailer.